[antlr-interest] Ambiguous lexing task

[Cliff Hudson]

I have a string which I need to parse for IDs and operators.  This is
normally pretty easy, but there is one case where a character in the ID can
also match one character in the operator.  The tokens are:

OP_TRANSFORM : '->'

ID : (LETTER | '_') (options { greedy=true } : NAMECHAR)*

fragment NAMECHAR : LETTER | DIGIT | '_' | '-' ;

LETTER : 'a'..'z' | 'A'..'Z' ;
NUMBER: '0'..'9' ;


The issue is in parsing the following string:

my-identifier->foo

The ID token of course matches 'my-identifier-', and then I am left with an
extraneous '>'.  Is there a way to construct a set of lexing rules, possibly
with actions, that would correctly separate out the -> from the ID?  In this
case, I want the '-' in OP_TRANSFORM to be the preferred path and to match
'->' even in the above case.

Thanks.